High rate actuators



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INVENTOR United States Patent 3,093,118 HIGH RATE ACTUATORS Boniard I. Brown, West Covina, Califi, assignor to General Dynamics Corporation (Convair Division), San Diego, Calif., a corporation of Delaware Filed Feb. 24, 1961, Ser. No. 91,436 19 Claims. (Cl. 121-68) The present invention is related to the invention described and claimed in the copending application of Boniard I. Brown, Serial No. 38,844, filed June 27, 1960 for High Energy Rate Actuator, which represents improvements upon the inventions of certain earlier applications identified in the copending application. The actuator of the above-identified application comprises a wall and a piston cooperable with the wall to provide a pressure seal therebetween about an enclosed portion of the wall. The piston is urged toward the wall to establish the pressure seal by a set force, which is preferably exerted by a set pressure which is established in a chamber on the side of the piston opposite from the Wall. An actuating pressure exerts force on an area of the piston outside the pressure seal. The set force is overbalanced either by increasing the actuating pressure to increase the force on the piston area outside the seal, or by applying a separate triggering force to the piston or to a thrust column attached to the piston. The overbalancing unseats the piston from the wall and suddenly eliminates the pressure seal, thereby releasing the actuating pressure upon a piston area within the seal and rapidly impelling the piston from the wall. T he triggering force may be provided by applying pressure to the piston area within the pressure seal. An output thrust-time pattern may be controlled by cooperation between a metering member on the wall and a cavity in the piston during the rapid movement of the piston from the Wall.

The above-described actuator of the copending application has certain of the disadvantages which characterize the earlier inventions hereinbefore mentioned. These disadvantages relate to the exertion of the set force in preferred embodiments by a separate set pressure. A separate set pressure system and set pressure chamber require special features and components. A somewhat complicated structure is therefore required. Upon the impelling of an actuator piston from a wall, the set pressure exerts force opposing the output thrust stroke of the piston, thereby reducing output thrust and efiiciency. Alhough the above-described invention provides greatly improved access of actuating pressure to the moving piston during its output stroke, in comparison with prior art devices, the provision of a set pressure chamber tends to involve some restriction of such application of the actuating pressure.

The improved actuator of the present invention comprises a thrust member having a head portion which is cooperable with a wall to provide a pressure seal therebetween about an enclosed portion of the wall. An actuating pressure exerts a set force on an effective transverse area of the thrust member to urge the head portion toward the wall to effect the pressure seal. A triggering force is applied to the thrust member to overbalance the set force, thereby disengaging the pressure seal and releasing the actuating pressure upon an area of the head portion. The thrust member is thus impelled from the wall to produce useful output thrust. Preferably, the head portion has a head surface confronting the wall, and the thrust column has an effective transverse area spaced axially from the head surface and facing substantially oppositely from the head surface. The pressure seal is preferably effected by a resilient sealing element positioned between the wall and the head portion. A triggering pressure, which may ice be the same as the actuating pressure, may be applied to an area of the head portion to exert the triggering force. To produce a predetermined thrust-time output pattern, a contoured metering member may be provided to cooperate with a cavity surface to regulate the release of the actuating pressure to the moving thrust member. A predetermined deceleration pattern may be provided by a deceleration pin portion on the thrust member which moves into a cooperating aperture. In certain preferred embodiments, the set force is exerted by the actuating pressure on the deceleration pin portion of the thrust member.

The present invention provides distinct advantages over the above-described invention of the copending application and over the actuators of the earlier applications identified in the copending application. Only a single pressure is required for providing a set force and the actuating force. A second pressure supply system is not required and special actuator features and components are not required to accommodate a second pressure. A considerably simplified and more economical construction may therefore be utilized. Efliciency and output thrust are improved, because there is no set pressure force opposing the actuator output stroke. Efiiciency and output thrust are not substantially affected by internal forces.

The invention generally provides the advantages of the invention of the copending application. An important advantage is that improved efliciency and output thrust result from improved access of the actuating pressure to the thrust member and efficient maintenance of the pressure on the thrust member during its output stroke. Actuators of the present invention provide substantially unrestricted access to the thrust member head portion during the output stroke. Relatively large actuating pressure chambers may convenienly be provided to further facilitate the maintenance of pressure against the thrust member.

It is therefore an object of the present invention to provide a new and improved high rate actuator.

An object of the invention is the provision of an improved actuator which generally achieves the objects of the previous inventions herein mentioned.

It is an object of the invention to provide an improved high rate actuator which requires only a single pressure for initiating operation and for exerting actuating force.

An object of this invention is to provide an improved high rate actuator according to the foregoing objects wherein an actuating pressure exerts a set force on an efiective transverse area of a thrust member.

It is an object of the present invention to provide an improved actuator wherein .an actuating pressure exerts a set force on an area of a thrust member to urge the thrust member toward a wall to effect a pressure seal therebetween, and wherein a triggering force is applied to the thrust member to overb-al ance the set force and release the actuating pres-sure upon a head pontion area of the thrust member.

An object of this invention is the provision of a high rate actuator which provides improved efficiency and output thrust through improved access of actuating pressure to a thrust column during an output stroke.

It is an object of the invention to provide an improved high rate actuator the output and efficiency of which are not substantially reduced by internal forces or losses.

An object of the present invention is to provide an improved high rate actuator of simplified and econmical construction.

It is an object of the invention to provide an actuator wherein an output thrust-time pattern is controlled by a contoured metering member.

Another object of the invention is the provision of an improved high rate actuator wherein a single pressure exerts a set force, is released upon a thrust member to exert output thrust, and is metered through an aperture to produce decelerating force.

Other objects, features and advantages of the present invention will become apparent to those versed in the art from a consideration of the following description, the appended claims and the accompanying drawings, wherein:

FIGURE 1 is an elevational View, partially in section, of a preferred embodiment of the actuator of the present invention;

FIGURES 2, 3 'and- 4 are fragmentary sectional views showing guidance and support components for use with the actuator of FIGURE 1;

FIGURE 5 is an elevation-a1 sectional view of an embodiment of the invention wherein a metering member provides a predetermined thrust-time output pattern;

FIGURE 6 is an enlarged fragmentary view showing certain elements of the actuator of FIGURE 5 in opera- *tion to produce a thrust-time output pattern;

FIGURE 7 is a fragmentary sectional view showing a metering pin and cavity of a modified form of the actuator of FIGURE 5;

FIGURE 8 is an elevational view, partially in section, of another embodiment of the present invention; and

FIGURE 9 is an elevational view, partially in section, of another embodiment of the invention.

Referring to the drawings, and particularly to FIG- URE 1, there is shown a preferred embodiment of the actuator of the present invention. The actuator has a housing assembly formed by -a wall member 10, an end member 12 and a cylinder 14, which are secured in clamped relation by tie-bolts 16. Each tie-bolt extends through an appropriate opening 18 in a flange portion of end member 12 and is secured in a threaded opening 20 in a flange portion of wall member 10. The assembly is secured to a mounting plate 22 by bolts 24, which extend thnough plate openings into threaded engagement with the wall member 10, as shown. A generally cylindrical actuating pressure chamber 26 is defined by the housing, and pressure sealing for the chamber is provided by resilient seal rings 28 adjacent to respective end portions of cylinder 14 in appropriate an- :nular grooves in the wall member and end member.

An output thrust member or column 30 is axially disposed in the housing and is slidably mounted in an annular bearing 32 which is threadedly secured in an opening in the end member 12. A sealing ring 34 in a bearing groove provides pressure sealing about the thrust column. A die part 36 is defined in the outer end portion of the thrust member and confronts a cooperating die part 38, which is secured to a foundation or wall 40 by bolts 42.

An enlarged head portion 44 is provided at the inner end of the thrust member. The head portion has a back surface 46 and includes a circular seal plate 48 which is secured to the end of the column by screws 50, as shown. A resilient annular sealing element 52 is secured as by bonding in an annular groove in the seal plate and extends therefrom to contact the wall member 10. The resilient sealing element 52 is adapted for cooperation with the wall to eiTect a circular pressure seal between the head portion and the wall about a closed portion of the wall and about an area of the head portion, when the thrust column is urged toward the wall member. The sealing element 52 and the circular pressure seal which it provides define an annular area 54 radially outside the pressure seal and encompass a circular area 56 of the head surface of the thrust column.

From the foregoing, it will be understood that a head portion of the thrust member has a head surface confronting a wall, and that the thrust member has an effective transverse area axially spaced from a head surface of the head portion. The head surface and the effective transverse area face substantially oppositely.

A passage 58 in wall member 10 and a fluid coupling 60 interconnect the actuating pressure chamber 26 with a supply of actuating pressure (not shown). A similar passage 62 in the wall member and a fluid coupling 64 connect the piston area 56 within the sealing element 52 with a source of triggering pressure (not shown), which may be the same as the source of actuating pressure.

FIGURES 2, 3 and 4 illustrate certain components and modifications which may be utilized with the actuator of FIGURE 1 to provide guidance and support for the movable thrust member. FIGURE 2 shows a guide rod for this purpose which is formed integrally with a thrust column 68. The guide rod extends through an axial opening in a wall member and is slidably received in a bearing 72 threadedly secured in the wall member. Pressure sealing between the guide rod and the wall member is provided by a sealing ring 74 adjacent to the bearing in the wall opening. A guidance and support rim 76 is shown in FIGURE 3. The rim is mounted on the thrust member by spokes 78 and is slidable in the cylinder 14. Shown in FIGURE 4 is a tubular guide member 30. Guide member 80 is threadedly secured in an opening 82 in the wall member and extends through an axial opening 84 in head portion 44 and through 'an axial bore 86 of a modified thrust column 83.

To prepare the actuator of FIGURE 1 for operation, the thrust member 30 is moved by external force to the position shown in FIGURE 1, wherein the head portion 44 is adjacent to the Wall member 16 and the annular resilient sealing element 52 engages the wall. A relatively high actuating pressure is introduced into the actuating pressure chamber 26 through coupling 60 and passage 58. The actuating pressure acts upon the effective transverse area of back surface 46 of the head portion 44, and thereby exerts a set force which urges the head portion toward the wall member 10 and compresses the resilient sealing element 52 against the surface of the wall member. The resilient sealing element 52 thereby effects a positive pressure seal about a portion of the wall and about an area of the head surface of the head portion 44. The positive pressure seal remains effective even when there is substantially no net force urging the head portion toward the wall, as when the forces on the thrust member are substantially balanced. The actuating pressure also exerts force on the annular piston area 54 radially outside the pressure seal, this force opposing the set force.

To operate the actuator, the set force is overbalanced by a triggering force to release the actuating pressure over an area of the head portion 44. The triggering force may be applied to the thrust member in various ways, such as the application of external mechanical force. It may preferably be applied by applying a triggering pressure to an area of the head portion. A triggering pressure may be introduced through the coupling 64 and the passage 62 to the area 56 of the head surface within the circular pressure seal at the annular resilient sealing element 52. The triggering pressure must be sufficient to overbalance the set force by cooperating with the force on the area 54 outside the pressure seal.

The overbalancing action of the triggering pressure unseats the thrust member head portion and suddenly disengages the resilient sealing element 52 from the wall member 10. The resilient element 52 maintains a positive pressure seal up to the instant of its disengagement, whereupon the actuating pressure is released substantially instantaneously upon the area 56 within the pressure seal. The thrust member is suddenly impelled with great force from the wall to produce high rate output thrust.

From the drawing and the foregoing description, it will be appreciated that the actuating pressure has free access to the head surface of the thrust member after the unseating of the head portion from the wall member. Actuating pressure is thus effectively maintained against the rapidly moving thrust member without substantian restriction. High output thrust and efficiency are therefore achieved.

The outer end portion or die part 36 of the thrust member impacts a workpiece which is shown positioned in the cooperating die part 38. Thrust member movement is thereby stopped, and special structure is not required to effect deceleration. A finished part formed by the rap d application of energy by the thrust member is shown in phantom outline in the die part 38.

To prepare the actuator for repeat operatiomthe thrust member head portion 44 is reseated against wall member by the application of external force to the thrust member.

Upon the reseating of the thrust member head portion 44, the trapping of pressure in the space defined by wall member 10, the annular sealing element 52 and the head portion surface area 56 within the pressure seal, is prevented by relieving pressure through the passage 62 and the coupling 64. Pressure such as the actuating pressure trapped in this space would act on the head portion area 56 to oppose the set force exerted on the effective transverse area of head portion back surface 46 by the actuating pressure. A small triggering force or low triggering pressure would then effect movement of the thrust member from the wall member. This would prevent etfective triggering and cause premature slow movement of the thrust column, thereby preventing effective operation of the actuator.

FIGURE 5 illustrates an embodiment of the invention which differs from the actuator of FIGURE 1 in that it utilizes a metering member to control an output thrusttime pattern, and in that it is provided with internal means for decelerating the thrust member. The actuator includes a housing assembly formed by a base or wall member 90, an end member 92, a bearing and separation wall 94, an apertured plate member 96 and cylindrical sections 98, 100, 102, all of which are secured in clamped relation by tie-bolts 104, as shown. The tie-bolts extend through appropriate openings 106 in a flange portion of end member 92 and are secured in threaded openings 168 in a flange portion of wall member 90. The assembly is secured to a foundation or mounting member 110 by bolts 112 which extend through openings in the foundation member and are threadedly secured in the wall member.

The cylindrical housing is divided into an actuating pressure chamber 114 and a reseating pressure chamber 116 by the bearing or separation wall 94. Pressure sealing for the chambers 114, 116 is provided by resilient seal rings 118 positioned adjacent to the cylindrical sections in annular grooves in the base member 90, end member 92, hearing wall 94 and plate member 96, as shown.

An output thrust member or column 120 is axially disposed in the housing and is slidably mounted in an annular bearing 122 in a large axial opening in the separation wall 94. A sealing ring in a bearing groove provides pressure sealing about the thrust column.

An axial cavity or opening 124 in the end of thrust member confronts wall member 90. The cavity has a cylindrical inner surface 126 and an end wall 128.

An enlarged head portion 130 of the thrust member confronts the wall member 90. Annular seal plate 132 is secured by screws 134 to the end of the thrust member about the opening of cavity 124. Pressure sealing between the seal plate and the thrust member is provided by a sealing ring in a seal plate groove.

It will be understood that the area of seal plate 132 about the cavity and the end wall 128 of the cavity consti'tute an elfective head surface which is in substantially confronting relation with the wall member 90. The head portion has a back surface like that of the actuator of FIGURE 1, which provides an effective transverse area of the thrust member.

An annular resilient sealing element 136' is secured as by bonding in an annular groove in the seal plate and extends therefrom for engagement with the wall member. As shown in FIGURES 5 and 6, an annular area 138 of the head surface is outside the circular pressure seal, and an annular area 140 is within the seal, together with the end wall 128 of cavity 124.

A metering member 142 is mounted on wall member 90 by engagement of its threaded shank portion 144 in an axial opening in the wall member. The metering member has an enlarged cylindrical portion which fits closely within cylindrical surface 126 of the cavity, and which has a contoured portion 143 for controlling a thrust pattern in the manner hereinafter described.

The thrust member has an integral flange which is disposed in the chamber 116 and which is in sliding engagement with cylindrical section 100. A sealing ring 152 in a peripheral groove of the flange provides pressure sealing between the cylindrical section and the flange. An annular space 154 is defined between the flange and the separation wall 94.

A deceleration pin portion 156 of the thrust member has a contoured axially extending peripheral surface 158 for cooperation with an aperture 160 in the plate member 96, for a purpose which is hereinafter described. De celeration portion 156 presents an effective transverse area which faces substantially oppositely from the head surface of head portion 130. A portion of the set force may be exerted on this transverse area in the operation of the actuator.

A passage 162 in wall member 90 and a fluid coupling 164 connect the actuating pressure chamber 114 with a source of actuating pressure (not shown). A similar passage 166 and a fluid coupling 163 provide communication between the head portion surface confronting the wall and a source of triggering prwsure (not shown), which may be the same as the actuating pressure. A port 170 in cylindrical section 102 and a fluid coupling 17 2 connect reseating pressure chamber 116 with a source of pressure (not shown). A passage 174 in the support wall 94 communicates between the space 154 and the exterior atmosphere.

FIGURE 7 illustrates a modified form of the actuator of FIGURE 5 wherein an alternative metering pin and cavity arrangement is utilized. A cavity 176 is defined in a modified wall member 178. Instead of being mounted on a wall member, the metering member 142 has its threaded shank portion secured in an opening in the thrust member, and secures a modified seal plate 180 to the head portion of the thrust member.

The operation of the actuator of FIGURE 5 is like that hereinbefore described in relation to the actuator of FIGURE 1, except that the metering member functions to control the acceleration phase of a predetermined thrust-time output pattern, and except for the function of the deceleration metering pin portion 156 in controlling the deceleration phase of a thrust-time output pattern. The operation also differs in that a portion of the set force may be exerted by the action of pressure in reseating pressure chamber 116 on the deceleration pin portion 156 and flange 150.

Upon the elimination of the pressure seal at the resilient sealing element 136 by the initial unseating movement of the thrust member, actuating pressure is released upon the head portion area within the resilient sealing element through a net flow area defined between the contoured portion 148 of the metering member and the cylindrical surface 126 of the cavity 124, or the surface 126 of the cavity 176 in the case of the form shown in FIGURE 7.

FIGURE 6- indicates the definition of this net flow area between the surface 126 and the metering member contoured portion 148 during the output stroke of the thrust member. The metering member thus governs a variation in net flow area and effects a correspondingly varying pressure drop across this flow area. The output thrust or force on the thrust member therefore varies in accordance with the net flow area. The enlarged portion 146 of the metering member fits closely within surface 126 to prevent premature undesired thrust on the thrust member. Selected thrust-time patterns may be produced by appropriate metering pins. A method of determining appropriate metering pin contours for selected thrust-time output patterns is described in United States Patent No. 2,949,096 to Jack B. Ot-testad and Samuel A. Skeen. During the output stroke of the thrust member, air is drawn into the space 154 through the passage 174 substantially to prevent the creation of a partial vacuum in this space which would reduce output thrust. The flange 150 may assist in decelerating the thrust column by compressing gas in the reseating pressure chamber 116. The separation wall 94 separates the actuating pressure from the flange 150. If the actuating pressure acted on the flange, no not set force could be exerted on the head portion back surface, and the triggering of the actuator could not be effected.

After the completion of the acceleration phase of a thrust-time output pattern, the deceleration metering pin portion 156 cooperates with apertured plate member 96 to effect a predetermined deceleration pattern. The contoured surface 153 of the pin portion regulates a net aperture flow area to control the flow through the aperture. The net flow area varies in accordance with the longitudinal contour of the deceleration pin. A desired deceleration-time pattern is obtained by appropriate contouring, as explained in the above-identified patent.

To prepare for repeat operation, head portion 130 is reseated against wall member 90. This may be effected by external force on the thrust member, as in the reseating of the thrust member of the actuator of FIGURE 1. Preferably, reseating is effected by the introduction into chamber 116 of a reseating pressure through coupling 172 and opening 170. The reseating pressure exerts force on the flange 150 to move the thrust column and head portion 130 toward wall member 90. The passage 174 prevents compression in the space 154, and thereby facilitates reseating. The force on flange 150 must be greater than the force exerted oppositely by the actuating pressure on the head portion. After reseating, the reseating pressure may be relieved through opening 170 and passage 172. The trapping of the actuating pressure in the space defined within the resilient sealing element 136, the head portion and wall member 90, is relieved in the manner hereinbefore described in relation to the actuator of FIG- URE 1.

In FIGURE 8 is shown an embodiment of the invention which is somewhat similar to the actuator of FIG- URE 5, but is more simplified by the elimination of the separation wall 94, the flange 150, the reseating pressure chamber and the reseating pressure system. The operation of the actuator is similar to that hereinbefore described for the actuator of FIGURE 5. The operation differs in that set force is exerted by the actuating pressure on the effective transverse area of the deceleration pin portion 156, as well as on the back surface of the head portion. It also differs in that the actuating pressure acts on the deceleration pin portion to exert the decelerating force on the thrust member, instead of a reseating pressure being thus metered. Therefore, a sin- 'gle pressure, the actuating pressure, provides a set force, provides the actuating force, and provides the decelerating force. The actuating pressure may also be utilized as a triggering pressure.

FIGURE *9 illustrates another actuator of the invention, which is generally similar in structure and operation to the actuator of FIGURE 8. -It differs from the actuator of FIGURE 8 in that the head portion of the thrust member is not enlarged. All of the set force is provided by the action of the actuating pressure on the effective transverse area of the deceleration metering pin portion 156. The operation of the actuator is otherwise similar to the operation of the actuators of FIGURES and 8.

From the foregoing description, those versed in the art will appreciate that the present invention achieves the objects and realizes the advantages hereinbefore mentioned, as well as the objects and advantages described in the patent and copending application herein mentioned.

Although specific embodiments of the present invention have been illustrated and described herein, it will be understood that the same are merely exemplary of presently preferred embodiments capable of attaining the objects and advantages hereinbefore mentioned, and that the invention is not limited thereto; numerous variations will be readily apparent to those versed in the art, and the invention is entitled to the broadest interpretation within the terms of the appended claims.

The inventor claims:

1. An actuator comprising means defining a wall, a thrust member having a head portion cooperable with the wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid, said thrust member and head portion being disposed in the actuating pressure fluid, means for applying the actuating pressure fluid to the thrust member to exert a set force urging the thrust member toward the wall to effect said pressure seal between the head portion and the wall, and means for applying a triggering force to the thrust member to overbalance the set force to disengage the pressure seal and expose an area of said head portion to the actuating pressure fluid, whereby the thrust member is impelled from the wall to produce output thrust.

2. An actuator comprising means defining a Wall, a thrust member having a head portion cooperable with the wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid, said thrust member and head portion being disposed in the actuating pressure fluid, an area associated with the thrust member and positioned for the exertion thereon by the actuating pressure fluid of a set force to urge the head portion toward the wall to effect said pressure seal, and means for applying a triggering force to the thrust member to overbalance the set force to disengage the pressure seal and expose an area of said head portion to the actuating pressure fluid, whereby the thrust member is impelled from the wall to produce output thrust.

3. An actuator comprising means defining a wall, a thrust member having a head portion confronting the wall, resilient sealing means positioned between the head portion and the wall for effecting a pressure seal therebetween about a portion of the wall and an area of the thrust member head portion, means establishing an actuating pressure fluid, said thrust member and head portion being disposed in the actuating pressure fluid, an area associated with the thrust member and positioned for the exertion of a set force thereon by the actuating pressure fluid to urge the head portion toward the wall to effect said pressure seal, and means for applying a triggering force to the thrust member to overbalance the set force to disengage the pressure seal and release the actuating pressure fluid upon said head portion area within said sealing means, whereby the thrust member is impelled from the wall to produce output thrust.

4. An actuator comprising means defining a wall in the actuator, an output thrust member having a head portion with a head surface substantially confronting the wall, said head portion being adapted to cooperate with the wall to provide a pressure seal therebetween about a por tion of the wall, means establishing an actuating pressure fluid in the actuator, said thrust member and head portion being disposed in the actuating pressure fluid, means defining an effective transverse area on the thrust member facing substantially oppositely from said head surface, said actuating pressure fluid acting on said transverse area to exert a set force urging the head portion toward the Wall to effect said pressure seal, and means for applying a triggering force to the thrust member to overbalance the set force to disengage the pressure seal and expose an 9 area of the head portion surface to the actuating pressure fluid, whereby the thrust member is impelled from the wall to produce output thrust.

5. An actuator comprising means defining a wall in the actuator, an output thrust member having a head portion with a head surface substantially confronting the wall, said head portion being adapted to cooperate with the wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid in the actuator, said thrust member and head portion being disposed in the actuating pressure fluid, means defining an etfeotive transverse area on the thrust member facing substantially oppositely from said head surface, said actuating pressure fluid acting on said transverse area to exert a set force urging the head portion toward the wall to effect said pressure seal, and means for applying a triggering pressure to said head surface to overbalance the set force to disengage the pressure seal and release the actuating pressure fluid upon an area of the head surface, whereby the thrust member is impelled from the wall to produce output thrust.

6. An actuator comprising means defining a wall, an output thrust column axially disposed in the actuator and extending therefrom, said thrust column having a head portion with a head surface substantially confronting the Wall and having an effectively transverse area spaced axially from the head surface and facing substantially oppositely therefrom, said head portion and the wall being cooperable to provide a pressure seal therebetween about an area of the head surface and an area of the wall, means establishing an actuating pressure fluid in the actuator, said thrust column and head portion being disposed in the actuating pressure fluid, said actuating pressure fluid acting on said effective transverse area to urge the head portion toward the wall to effect said pressure seal, and means for applying a triggering force to the thrust column to overbalance said set force to eliminate the pressure seal and release the actuating pressure fluid upon said head surface area within the seal, whereby the thrust column is impelled from the Wall to produce output thrust.

7. An actuator comprising means defining a wall, an output thrust column axially disposed in the actuator and extending therefrom said thrust column having a head portion with a head surface substantially confronting the wall and having an effective transverse area spaced axially from the head surface and facing substantially oppositely therefrom, resilient sealing means positioned between said head portion and the wall for effecting a pressure seal therebetween about an area of the head surface and an area of the wall, means establishing an actuating pressure fluid in the actuator, said thrust column and head portion being disposed in the actuating pressure fluid, said actuating pressure fluid acting on said effective transverse area to urge the head portion toward the wall to effect said pressure seal, and means for applying triggering pressure to the head surface to overbalance the set force to eliminate the pressure seal and release the actuating pressure fluid upon the head surface area within the pressure seal, whereby the thrust column is impelled from the wall to produce useful output thrust.

8. An actuator comprising means defining a wall, an output thrust member having an enlarged head portion cooperable with the wall to provide a pressure seal therebetween about a surface portion of the wall, said head portion having a head surface substantially confronting the wall and having a substantially oppositely facing back surface, means establishing an actuating pressure fluid in the actuator, said thrust member and head portion being disposed in the actuating pressure fluid, said actuating pressure fluid acting on said head portion back surface to exert a set force urging the head portion toward the wall to effect said pressure seal, and means for applying a triggering force to the thrust member to disengage the pressure seal and expose an area of the head surface it to the actuating pressure fluid, whereby the thrust member is impelled from the wall to produce output thrust.

9. An actuator comprising means defining a wall, an output thrust member having an enlarged head portion, said head portion having a head surface substantially confronting the wall and having a substantially oppositely facing back surface, a resilient sealing element positioned between the wall and the head surface for effecting a pressure seal therebetween about an area of the head sur face, means establishing an actuating pressure fluid in the actuator, said thrust member and head portion being disposed in the actuating pressure fluid, said actuating pressure fluid acting on said head portion back surface to exert a set force urging the head portion toward the wall to effect said pressure seal and means for applying a triggering force to the thrust member to disengage the pressure seal and expose said head surface area to the actuating pressure fluid,, whereby the thrust member is impelled from the wall to produce output thrust.

10. An actuator comprising means defining a wall, a thrust member having a head portion cooperable with the wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid, said thrust member and head portion being disposed in the actuating pressure fluid, an area associated with the thrust member and positioned for the exertion thereon by the actuating pressure fluid of a set force to urge the head portion toward the wall to effect said pressure seal, means for applying a triggering force to the thrust member to overbalanec the set force to disengage the pressure seal and release the actuating pressure fluid upon an area of said head portion, thereby impelling the thrust member from the wall, and a contoured metering member cooperating with means defining a cavity to regulate the release of the actuating pressure fluid to the moving thrust member to produce a predetermined thrusttime output pattern.

11. An actuator comprising means defining a wall having a cavity with an inner surface, a thrust member having a head portion cooperable with the Wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid, said thrust member and head portion being disposed in the actuating pressure fluid, an area associated with the thrust member and positioned for the exertion of a set force thereon by the actuating pressure fluid to urge the head portion toward the wall to effect said pressure seal, means for applying a triggering force to the thrust member to over balance the set force to disengage the pressure seal and release the actuating pressure fluid upon an area of said head portion, thereby impelling the thrust member from the wall, and a contoured metering member on the head portion for cooperation with said cavity surface to regulate flow to the moving thrust member to produce predetermined thrust-time output pattern.

12. An actuator comprising means defining a wall in the actuator, an output thrust member having a head portion with a head surface substantially confronting the wall, said head portion being adapted to cooperate with the wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid in the actuator, said thrust member and head portion being disposed in the actuating pressure fluid, means defining an effective transverse area on the thrust member facing substantially oppositely from said head surface, said actuating pressure fluid acting on said transverse area to exert a set force urging the head portion toward the wall to effect said pressure seal, means for applying a triggering force to the thrust member to overbalance the set force to disengage the pressure seal and expose an area of the head portion surface to the actuating pressure fluid, thereby impelling the thrust member from the wall, said head portion defining a cavity having an inner surface and confronting the wall, and a contoured metering member on the wall to cooperate with 1 l the cavity surface to regulate flow to the moving thrust member to produce a predetermined thrust-time output pattern.

13. An actuator comprising a wall defining a cavity with an inner surface, an output thrust member having a head portion with a head surface substantially confronting the wall, said head portion being adapted to cooperate with the wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid in the actuator, said thrust member and head portion being disposed in the actuating pressure fluid, means defining an effective transverse area on the thrust member facing substantially oppositely from said head surface, said actuating pressure fluid acting on said transverse area to exert a set force urging the head portion toward the wall to effect said pressure seal, means for applying a triggering force to the thrust member to overbalance the set force to disengage the pressure seal and expose an area of the head portion surface to the actuating pressure fluid, thereby impelling the thrust member from the wall, and a contoured metering member on the head portion for cooperation with said wall cavity surface to regulate flow to the moving thrust member to produce predetermined thrust-time output pattern.

14. An actuator comprising means defining a Wall, a thrust member having a head portion cooperable with the wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid, said thrust member and head portion being disposed in the actuating pressure fluid, a deceleration pin portion carried by the thrust member and having an effective transverse area, said actuating pressure fluid exerting a set force on the transverse area to urge the head portion toward the wall to effect said pressure seal, means for applying a triggering force to the thrust member to overbalance the set force to disengage the pressure fluid seal and release the actuating pressure upon an area of said head portion, thereby impelling the thrust member from the wall, and means defining an aperture within the actuator, said deceleration pin portion moving into the aperture to regulate flow therethrough to develop predetermined variation in decelerating force on the thrust member.

15. An actuator comprising means defining a wall, a thrust member having a head portion cooperable with the wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid, said thrust member and head portion being disposed in the actuating pressure fluid, a deceleration pin portion carried by the thrust member and having an area positioned for the exertion of a set force thereon by the actuating pressure fluid to urge the head portion toward the wall to effect said pressure seal, means for applying a triggering force to the thrust member to ovcrbalance the set force to disengage the pressure seal and release the actuating pressure fluid upon an area of said head portion, thereby impelling the thrust member from the wall to produce output thrust, and means defining an aperture within the actuator, said deceleration pin moving into the aperture to regulate flow therethrough to develop predetermined variation in decelerating force on the thrust member.

16. An actuator comprising means defining a wall, a thrust member having a head portion cooperable with the wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid, said thrust member and head portion being disposed in the actuating pressure fluid, a deceleration pin portion carried by the thrust member and having an effective transverse area, said actuating pressure fluid acting on said transverse area to exert a set force urging the head portion toward the wall to effect said pressure seal, means for applying a triggering force to the thrust member to overbalance the set force to disengage the pressure seal and expose an area of said head portion to the actuating pressure fluid, thereby impelling the thrust member from the wall, a contoured metering member cooperating with means defining a cavity to regulate the release of the actuatingpressure to the moving thrust member to produce a predetermined thrust-time output pattern, means defining an aperture within the actuator, said deceleration pin portion moving into the aperture to regulate flow therethrough to develop predetermined variation in decelerating force on the thrust, member.

17. An actuator comprising a wall having a cavity with an inner surface, an output thrust member having a head portion with a head surface substantially confronting the wall, said head portion being adapted to cooperate with the Wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid in the actuator, said thrust member and head portion being disposed in the actuating pressure fluid, means defining an area on the thrust member facing substantially oppositely from said head surface, said means including a deceleration pin portion carried by the thrust member and having an effective transverse area, said actuating pressure fluid acting on said thrust member area to exert a set force urging the head portion toward the wall to effect said pressure seal, means for applying a triggering force to the thrust member to :overbalance the set force to disengage the pressure seal and expose an area of said head portion to the actuating pressure fluid, thereby impelling the thrust member from the wall to produce output thrust, a contoured metering member on the thrust member to cooperate With said Wall cavity inner surface to regulate flow to the moving thrust member to produce a predetermined thrust-time output pattern, and means defining an aperture within the actuator, said deceleration pin portion moving into the aperture to regulate flow therethrough to develop predetermined variation in decelerating force on the thrust-member.

18. An actuator comprising means defining a wall, an output thrust member having a head portion with a head surface substantially confronting the wall, said head portion being adapted to cooperate with the wall to provide a pressure seal therebetween about a portion of the wall, means establishing an actuating pressure fluid in the actuator, said thrust member and head portion being disposed in the actuating pressure fluid, means defining an area on the thrust member facing substantially oppositely from said head surface, said means including a deceleration pin portion carried by the thrust member and having an effective transverse area, said actuating pressure fluid acting on said thrust member area to exert a set force urging the head portion toward the wall to effect said pressure seal, means for applying a triggering force to the thrust member to overbalance the set force to disengage the pressure seal and expose an area of said head portion to the actuating pressure fluid, thereby impelling the thrust member from the wall to produce output t rust, said head portion defining a cavity having an inner surface and confronting the wall, a contoured metering member on the wall to cooperate with the cavity surface to regulate flow to the moving thrust member to produce a predetermined thrust-time output pattern, and means defining an aperture within the actuator, said deceleration pin portion moving into the aperture to regulate flow therethrough to develop predetermined variation in decelerating force on the thrust member.

19. An actuator comprising means defining a wall, an output thrust column axially disposed in the actuator and extending therefrom, said thrust member having a head portion With a head surface substantially confronting the wall and having an effectively transverse area spaced axially from the head surface and facing substantially oppositely therefrom, said head portion and the Wall being cooperable to provide a pressure seal therebetween about an area of the head surface and a portion of the wall, means establishing an actuating pressure 13 fluid in the actuator, said thrust member and head portion being disposed in the actuating pressure fluid, said actuating pressure fluid acting on said eifective transverse area to urge the head portion toward the Wall to eflieet said pressure seal, said pressure seal defining an area of said head portion surface, means for applying a triggering force to the thrust column to overbalanee said set force to eliminate the pressure seal and release the actuating pressure fluid upon said head surface area defined :by the seal, thereby impelling the thrust column from the wall to produce useful output thrust, and means for applying a :reseating pressure to the thrust column to reposition said portion relative to said wall preparatory 5 to repeat operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,740,859 Beatty et a1 Apr. 3, 1956 

1. AN ACTUATOR COMPRISING MEANS DEFINING A WALL, A THRUST MEMBER HAVING A HEAD PORTION COOPERABLE WITH THE WALL TO PROVIDE A PRESSURE SEAL THEREBETWEEN ABOUT A PORTION OF THE WALL, MEANS ESTABLISHING AN ACTUATING PRESSURE FLUID, SAID THRUST MEMBER AND HEAD PORTION BEING DISPOSED IN THE ACTUATING PRESSURE FLUID, MEANS FOR APPLYING THE ACTUATING PRESSURE FLUID TO THE THRUST MEMBER TO EXERT A SET FORCE URGING THE THRUST MEMBER TOWARD THE WALL TO EFFECT SAID PRESSURE SEAL BETWEEN THE HEAD PORTION AND THE WALL, AND MEANS FOR APPLYING A TRIGGERING FORCE TO THE THRUST MEMBER TO OVERBALANCE THE SET FORCE TO DISENGAGE THE PRESSURE SEAL AND EXPOSE AN AREA OF SAID HEAD PORTION TO THE ACTUATING PRESSURE FLUID, WHEREBY THE THRUST MEMBER IS IMPELLED FROM THE WALL TO PRODUCE OUTPUT THRUST. 